AWS WAF Blocked Requests Surge and L7 Attack Sentinel

id: aws-waf-blocked-requests-surge-sentinel
namespace: company.security

inputs:
  - id: aws_region
    type: STRING
    defaults: us-east-1
    description: AWS region where the WAF WebACL resides.
  - id: webacl_name
    type: STRING
    defaults: production-api-webacl
    description: Name of the AWS WAF WebACL to monitor.
  - id: max_blocked_requests_threshold
    type: INT
    defaults: 200
    description: Maximum permissible blocked requests in a 15-minute window before
      triggering a security alert.

tasks:
  - id: query_waf_blocked_requests
    type: io.kestra.plugin.aws.cli.AwsCLI
    region: "{{ inputs.aws_region }}"
    accessKeyId: "{{ secret('AWS_ACCESS_KEY_ID') }}"
    secretKeyId: "{{ secret('AWS_SECRET_ACCESS_KEY') }}"
    commands:
      - |
        aws cloudwatch get-metric-statistics           --namespace AWS/WAFV2           --metric-name BlockedRequests           --dimensions Name=WebACL,Value="{{ inputs.webacl_name }}" Name=Region,Value="{{ inputs.aws_region }}" Name=Rule,Value=ALL           --start-time $(date -u -v-15m +%Y-%m-%dT%H:%M:%SZ 2>/dev/null || date -u -d "15 minutes ago" +%Y-%m-%dT%H:%M:%SZ)           --end-time $(date -u +%Y-%m-%dT%H:%M:%SZ)           --period 900           --statistics Sum           --output json > waf_blocks.json
        python3 -c "
        import json
        with open('waf_blocks.json') as f:
            dps = json.load(f).get('Datapoints', [])
        total_blocked = int(sum(dp.get('Sum', 0) for dp in dps))
        result = {
            'webacl_name': '{{ inputs.webacl_name }}',
            'blocked_requests': total_blocked,
            'alert_triggered': total_blocked > {{ inputs.max_blocked_requests_threshold }}
        }
        with open('waf_summary.json', 'w') as out:
            json.dump(result, out)
        print('WAF audit:', result)
        "
    outputFiles:
      - waf_summary.json

  - id: evaluate_waf_surge
    type: io.kestra.plugin.core.flow.If
    condition: "{{
      fromJson(read(outputs.query_waf_blocked_requests.outputFiles['waf_summary\
      .json'])).alert_triggered }}"
    then:
      - id: alert_soc_team
        type: io.kestra.plugin.slack.notifications.SlackIncomingWebhook
        url: "{{ secret('SLACK_WEBHOOK') }}"
        payload: |
          {
            "text": ":shield: *AWS WAF Security Alert*: WebACL `{{ inputs.webacl_name }}` blocked {{ fromJson(read(outputs.query_waf_blocked_requests.outputFiles['waf_summary.json'])).blocked_requests }} requests in the last 15 minutes. Potential credential stuffing, SQLi/XSS attack wave, or bot scraping surge."
          }

errors:
  - id: notify_sentinel_error
    type: io.kestra.plugin.slack.notifications.SlackIncomingWebhook
    url: "{{ secret('SLACK_WEBHOOK') }}"
    payload: |
      {
        "text": ":warning: *WAF Sentinel Failure*: Failed to query CloudWatch metrics for WebACL `{{ inputs.webacl_name }}`."
      }

triggers:
  - id: scheduled_waf_check
    type: io.kestra.plugin.core.trigger.Schedule
    cron: "*/15 * * * *"
    disabled: true